Fracturing is a subterranean well production enhancing technique where fractures are initiated in a target formation, propagated, and then supported in the open state, thereby allowing ultimate production to the surface. Packers have been set in open hole as a technique to initiate fractures as described in US Publication 2011/0139456. However, this technique preferably used compression set packers and sliding sleeves 22 that were located uphole from each packer that could be selectively opened for production. Another design shown in US Publication 2011/0284229 showed a series of inflatable packers that incorporated sliding sleeves that were shifted with a shifting tool on a service string such as coiled tubing to open ports above the inflatable which fully encircled the production string. This design involved another trip in the hole to open the ports and positioning of the ports remotely from the packer since the inflatable fully surrounded the production string.
Other references with some relevance to the present invention include U.S. Pat. Nos. 2,798,560 and 4,655,286.
In U.S. Pat. No. 5,295,393 an inflatable sleeve is used to initiate fractures. Isolation inflatable packers are then set above and below the initiation location and a zone is isolated so that that fluid can be pumped into the zone to propagate the fractures. The sleeve that initiated the fractures is deflated after inflation and is located midway in the interval between the inflatable isolation packers.
What is needed and provided by the present invention is a technique that uses a 360 degree inflatable member to initiate fractures and then in a variety of ways propagates the initiated fractures with high flow rates at high pressure in the vicinity of the fracture initiation. One way this is done is to rupture the inflatable after it has created the initial fractures. Another way is to inflate the inflatable to the desired pressure while providing a network of openings in the inflatable. With enough flow under proper pressure the inflatable can still inflate to initiate fractures but thereafter the openings allow continuation of flow at the fracture initiation location. In another variation fracture extension ports can be opened without wellbore intervention after the inflatable is inflated. In this variation a ball lands on a seat in a first shifting sleeve to open access to the inflatable to initiate the fracture and another sliding sleeve with a ball seat then accepts a different ball to shift open a port through which the already initiated fracture is further propagated. These and other aspects of the invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.